A flat panel type display device typified by a liquid crystal display device is characterized by thin-lightweight and low power consumption, etc. Further, technical development is promoted for improving display performances such as a colonization, a high definition, and/or a moving picture processing. Accordingly, at present, such a flat panel type display device is widely incorporated in an electronic device such as a mobile phone, a PDA, a DVD player, a mobile game machine, a laptop PC, a PC monitor, or a TV.
In these circumstances, in these years, a liquid crystal display device has been developing in which an optical sensor element is provided in each pixel (alternatively in one of pixels RGB) in a image display region (for example, refer to Patent Literature 1, Non Patent Literatures 1 and 2). In a case where an optical sensor element is thus provided in each pixel, even a normal liquid crystal device can achieve a scanning function and a touch panel function. That is, the optical sensor element serves as an area sensor.